Is spending $400 or more on an aftermarket exhaust worth it? They certainly sound better than stock but do they significantly increase power? I am the only one I know with stock exhaust on a CBR 600 or a crotch rocket at all.
Aftermarket exhaust systems are the biggest-selling accessory on -most- motorcycles, not just sportbikes but cruisers also. Only because some riders want them louder The manufacturers comply with Dept. of Transportation noise guideines, and bikers think the bikes sound more like sewing machines than motorcycles, so they get an aftermarket exhaust system to make them louder. It's all about decibels. I suppose a high-tech exhaust system could add 2 or 3 hp. But it would be part of an all-over tuning strategy, meaning new carb jets, maybe different cams, etc. 2 or 3 hp on a 120 hp bike wouldn't make that much of a difference, except maybe in racing. And you'd end up spending $1000 for that 3 hp, which wouldn't be worth it, except maybe in racing.
a high performance exhaust along with high a high flow air filter and a quick re map of the FI or jetting the carbs will give a HP increase. but the most notable part of an after market exhaust system is that it will change the power curve of the engine slightly. you will also shed a few pounds of extra weight. and like has been said its going to be louder
The solid ball will have more thermal energy to conduct to the ice, and is more likely to melt through the ice than the hollow ball. So the hollow ball will be the one remaining on the ice.
This question involves both specific heat capacity (the amount of heat per degree per unit mass) and total heat capacity (the product of specific heat capacity and mass). Both balls will have the same specific heat capacity but the ball with the most mass (solid) will have more total heat per degree of temperature rise. The solid ball will melt deeper into the ice than the hollow ball. In the limit, the hollow ball could be a very thin shell containing a vacuum and holding very little total heat).
Take the stock pipes off, compare the weight with an aftermarket set – there are several pounds difference. And, if a modern bike, there is a catalytic converter – not only heavy and expensive to produce, it will also be strangling some of your output. If you do change them – keep the originals (dry and protected).
